Work hold-down device



Nov. 12, 1946- c. R UBENSTEIN WORK HOLD-DOWN DEVICE Filed Dec. 26, 1944 INVENTOR. Ch /42.5 fiae/rsf/fl erromvzx ,of the machine, but lying support.

Patented Nov. 12, 1946 WORK HQ QW DEVI E :Char-les- 'Rubenstein, KansasCity, Mo.,

'ApplicationjDecember 26, 1944, Serial No. 569,752

' 3 Claims.

. This invention relates to attachments for work-holding machines in the character of shapers or the like, and has for-its primary aim to'provide means fordirectlyengaging the material constituting the work, and for securing said work not only between *the'retaining clamps tightly against the under- One of the primaryaims of this invention is to provide a work hold-down for shapers or the like, adapted for re-positiomng between the -material and the clamps and having at least one gspecially formed part, disposed to convert a portion of the pressure exerted by the clamps into force holding the work against the bed of the machine.

This invention has for an even further aim to provide a work hold-down of the aforementioned character, which includes a specially disposed blade, positioned at an angle with respect to the direction of travel of the retaining clamps, which blade is resilient, divided into sections, and specially designed to insure a positive grip and an engagement that will not accidentally loosen and which will preclude upward movement of the work from its normal place upon the surface of the machine bed.

Other objects of the invention will appear during the course of the following specification, referring to the accompanying drawing, wherein:

Fig. 1 is a front elevational view in perspective of a work hold-down made in accordance with the present invention and showing the same in operative position on a shaper.

Fig. 2 is a top plan view of the work hold-down per se.

Fig. 3 is an end elevational view thereof.

Fig. 4 is a cross sectional view through the hold-down, taken on line IV-IV of Fig. 2; and

Fig. 5 is a similar cross sectional view illustrating a hold-down made pursuant to a modified form of the invention.

Heretofore horizontally movable clamps for holding the material constituting work receiving attention, have failed to maintain the work in a position tight against the upper surface of the bed of the shaper. It is difficult to supplement the clamps or position the same to exert a downward pressure, and since such pressure is essential, the hold-down blocks embodying this invention are practically indispensable before the work can be perfectly set.

In the drawing wherein like reference characters refer to similar parts, the numeral Ill designates a shaper of conventional type having as a part thereof, a pair of opposed clamps I2 and.

I4 above a bed I6, and movable in;-horizontal paths thereabove. Inshort, the directiomof travel of clamps I2 and I4 is parallel to the top of 136C115, whereupon work- IB is positioned. The work, in this instance isillustratedqasa polygonal solid having opposed vertical surfaces 20, against which the-hereinafter described holddown members are forced.

The hold-down per se comprisesya bqdy 22 shaped, in its preferred embodiment as illustrated in Figs. 2, 3- and 4, and formed-of material capable of withstandingflthe pressureand' having resilient characteristicsto theend that-the downwardly and forwardly inclined *blade 24 -constituting a part thereof, may flex.

In the form illustrated, blade 24 is created by longitudinally milling body 22 to establish a groove 26. A tongue 28 is disposed below groove 23 to present a base for body 22. The edge of body 22 engaged by the adjacent clamps I2 or I4 as the case may be, is longitudinally milled to form a depression30 on either side of which is a flat face 32. These flat faces 32 are in the same vertical plane and face 34 of tongue 28 is at right angles to the plane wherein faces 32 are disposed.

The forward lowermost free edge of blade 24 is relatively thin and this edge 36 projects outwardly beyond the underlying edge 40 of tongue 38.

When the hold-down is in place, as illustrated in Fig. 1, faces 32 lie against the smooth inner surface of the adjacent clamp and surface 34 lies upon the normally horizontal face of bed I6. Inward movement of the clamp which exerts the force toward work I8, will drive edge 36 against work I8 and not only force said work downwardly against bed I6, but grip the same as would be the case if only clamps I2 and I4 were used.

A number of transverse slits 42 formed in blade 24 divide said blade 24 into a plurality of sections 44. Thus, any irregularity of the face of work I8 against which the hold-down is being moved, will not eifect the position or function of body 22. On the contrary, the several sections 44 will flex to different degrees to compensate for such irregularities and a positive inward and downward pressure will be applied to work I8.

In the modified form of the invention illustrated in Fig. 5, body I00 carries the flexible blade I02 assembled with body I00 after being separately manufactured. This blade is downwardly and forwardly inclined however, in the same manner as is blade 24, and its lowermost free edge I 04 projects beyond edge I06 of the body. A series of pins I08 projecting upwardly through 3 openings cooperate with groove H2 in maintaining blade I02 in the operative position illustrated in Fig. 5.

Body I00 is formed to present a fulcrum H4 about which plate I02 may rock. This rocking is limited by the width of groove 2 and when pressure is exerted against smooth surfaces H6, blade I02 will arch and increase the amount of force that is applied to the work in a direction toward the supporting underlying'bed I0.

Obviously, the basic function of both forms of the hold-down illustrated and described, is the same. The conversion of the pressure exerted by clamps l2 and [4 into force holding the work against the bed of the machine,.as well as holding the work between the clamps, is the resultcf using the hold-down blocks, and therefore, there is no danger of mal-adjustment due to unde-' sirable upward displacement of the work.

The manner of constructing hold-downs made accordance with this invention; and their specific appearance may be different from that above described and illustrated in the accompanying drawing. It is desired, therefore, to be limited only by the spirit ofthe invention and scope of the appended claims.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

. against the work in a direction substantially parallel to the top of the bed, said hold down comprising a body adapted for positioning between the work and said clamp, said body having a flexible, downwardly inclined, transversely archable portion formed to convert a portion of the pressure exerted in said direction into force holding the work against the bed of the machine, said resilient portion being divided into a plurality of independent sections all engaging the work and all receiving pressure from the clamp.

2. A hold down of the character described for use in material shaping machines having a work supporting bed and a clamp for exerting pressure against the work in a direction substantially parallel to the top of the bed, said hold down ,comprising a, body adapted for positioning between I the work and said'clamp, said body having a downwardly inclined flexible blade formed to arch as the pressure exerted in the aforesaid direction by the clamp is applied whereby a portionof said 7 pressure is converted into force'holdingthe' work against the bed of the machine, said blade'being transversely divided into a plurality of independing its length. 1

CHARLES RUBENSTEIN, 

